PMID: 27966990

 

    Legend: Sugar

Title : Site-Specific N-Glycosylation of Endothelial Cell Receptor Tyrosine Kinase VEGFR-2

Abstract :

1. Vascular endothelial growth factor receptor-2 ( VEGFR-2 ) is an important receptor tyrosine kinase ( RTK ) that plays critical roles in both physiologic and pathologic angiogenesis
2. The extracellular domain of VEGFR-2 is composed of seven immunoglobulin-like domains , each with multiple potential N-glycosylation sites (sequons)
3. N-glycosylation plays a central role in RTK ligand binding, trafficking, and stability
4. However, despite its importance, the functional role of N-glycosylation of VEGFR-2 remains poorly understood
5. The objectives of the present study were to characterize N-glycosylation sites in VEGFR-2 via enzymatic release of the glycans and concomitant incorporation of 18O into formerly N-glycosylated sites followed by tandem mass spectrometry (MS/MS) analysis to determine N-glycosylation site occupancy and the site-specific N-glycan heterogeneity of VEGFR-2 glycopeptides
6. The data demonstrated that all seven VEGFR-2 immunoglobulin-like domains have at least one occupied N-glycosylation site
7. MS/MS analyses of glycopeptides and deamidated, deglycosylated ( PNGase F-treated) peptides from ectopically expressed VEGFR-2 in porcine aortic endothelial (PAE) cells identified N-glycans at the majority of the 17 potential N-glycosylation sites on VEGFR-2 in a site-specific manner
8. The data presented here provide direct evidence for site-specific, heterogeneous N-glycosylation and N-glycosylation site occupancy on VEGFR-2
9. The study has important implications for the therapeutic targeting of VEGFR-2 , ligand binding, trafficking, and signaling